fix: remove unused import

Signed-off-by: Tom Carrio <[email protected]>

Author: tcarrio

open_feature/open_feature_client.py

@@ -20,7 +20,6 @@
     before_hooks,
     error_hooks,
 )
-from open_feature.immutable_dict.mapping_proxy_type import MappingProxyType
 from open_feature.open_feature_evaluation_context import api_evaluation_context
 from open_feature.provider.no_op_provider import NoOpProvider
 from open_feature.provider.provider import AbstractProvider
@@ -363,4 +362,3 @@ def _create_provider_evaluation(
             raise TypeMismatchError()
 
         return value
-